No, that doesn't fix it, the text stays white even after switching tabs, or scrolling or even selecting a block of text (including the non-coloured text).

I have just noticed that the colour the text goes to depends on what code the most recent edit took place on, so if it were:

object.aproperty = @"foo"

then the text takes on the colour of "aproperty", which in my case is blue (Twilight theme), this time the code lost its syntax colour up to the line that got reformatted but not beyond, whereas if I do this in a block of @synthesize statements at the top of the file the text goes white from the edit onwards, but not before.

Chris